1. Field
The present disclosure relates to thermal sensors, more particularly to continuous thermal/overheat sensing in aircraft and in vehicles.
2. Description of Related Art
Thermal sensing in aircraft components (e.g., a hot air duct from an engine for environmental control) can utilize heat-sensing elements disposed therein for monitoring the components for overheating. Current duct leak overheat detection systems (DLODS) use a nickel-containing inner core electrode and an Inconel 625 outer sheath electrode separated by a granular, porous ceramic or glass layer. This granular, porous ceramic layer is filled with a salt mixture and acts as an electrical barrier between electrodes when exposed below a threshold temperature. The salt mixture melts at a threshold temperature and causes electrical connection between the inner electrode and the outer electrode such that the salt mixture is a heat-sensing element.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved thermal sensors. For aircraft with polymer composite components, the overheat sensing needs to react at lower temperature with faster response. The present disclosure provides a solution for this need.